FORMATION OF WHITE ETCHING LAYER BY HIGH-PRESSURED SHEAR DEFORMATION ON THE RAIL SURFACE

The mechanism of White Etching Layers (WELs) formation via severe plastic deformation was examined. An experimental study was conducted, and large plastic deformation was produced by applying a combination of high-pressure and torsional straining on the rail steel material using a high-pressure torsion (HPT) system. The structure and microstructure evolution of the samples after testing were characterized and discussed. WEL was formed where the highest shear strain occurred. WELs from ex-service rail were also examined and characterized. The formation of a white layer on the pearlitic rail steel material subjected to quasi-hydrostatic pressured shearing provides strong evidence of mechanical induced WELs.